From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from majordomo by infradead.org with local (Exim 3.03 #1) id 11w4yM-0005rL-00 for mtd-list@infradead.org; Thu, 09 Dec 1999 14:55:10 +0000 Received: from [209.184.180.169] (helo=bob.faxtel.net) by infradead.org with esmtp (Exim 3.03 #1) id 11w4yL-0005rF-00 for mtd@imladris.mvhi.com; Thu, 09 Dec 1999 14:55:09 +0000 Message-ID: <384FC311.1E57CBD6@go2fax.com> Date: Thu, 09 Dec 1999 08:56:17 -0600 From: Bob Canup MIME-Version: 1.0 To: MTD Subject: Re: [Fwd: Power Down] References: <384ECF77.C1F5D6FC@danielind.com> <384EE388.C92A374E@go2fax.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-mtd@imladris.demon.co.uk List-ID: Bob Canup wrote: > Vipin Malik wrote: > > > Bob Canup wrote: > > > > > > I can't see any difference between erasing a bad sector after the next power > up and the case of a slightly earlier power failure where the data was never > written in the first place; you wind up with an identical file system in both > cases. If you can survive the case of the earlier power failure failing to > record the sector then you can survive the case of the bad sector being > erased. > > The only difference that I see is that in the case of the bad sector you > know something happened, in the case of the data never being recorded you > don't. > > To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org On the way home last night it occurred to me that if you are doing a read-modify-write cycle that it does make a difference where the error occurs. In this case if the sector is never written the old data is still valid. It seems to me the wear leveling necessary in a flash can be a benefit here; if I understand correctly we don't overwrite the physical pages - only when a page is 'committed' does the chip change its mapping so that it appears that the sector was overwritten. To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org